Medical personnel with the Texas Department of State Health Services are urging people to take precautions to reduce the risk of contracting West Nile virus, a mosquito borne illness. People should use insect repellent when outdoors and avoid going outside at dusk and dawn.

There has been a higher than usual number of human West Nile cases in Texas this year due to the warm winter and recent rains, particularly in the North Texas region. Statewide 111 human West Nile virus cases and one death have been reported to DSHS this year. Of those, 71 were West Nile neuroinvasive disease cases, and 40 were West Nile fever cases.

Approximately 80 percent of the cases reside in Dallas, Collin, Tarrant and Denton counties.

Over the past 10 years, 49 cases on average were reported to DSHS by this time each year, ranging from a low of three cases in 2011 to a high of 171 cases in 2006.

Humans can contract West Nile virus from a mosquito bite. Infected mosquitoes get the virus from feeding on infected birds and mammals. The virus can cause serious illness or death.

The milder form of the illness is West Nile fever. Symptoms include fever, headache, muscle and bone aches, nausea and drowsiness. People with the milder form of illness typically recover on their own, although symptoms may last for several weeks. Up to 80 percent of people infected with West Nile virus will have no symptoms and will recover on their own.

The intensity of West Nile virus activity in Texas fluctuates from year to year and depends on a variety of factors including the weather, the numbers of birds and mosquitoes that maintain and spread the virus and human behavior. The season can last up until the first hard freeze of the year.

There are no medications to treat or vaccines to prevent West Nile virus infection. People over 50 years old and those with compromised immune systems are at a higher risk of becoming seriously ill when they become infected with the virus.

People with symptoms that cause concern are urged to contact their healthcare provider.

Ways to reduce exposure to West Nile virus include:

• Always use an approved insect repellent when outside and follow the instructions on the label. Approved repellents are those that contain DEET, picaridin or oil of lemon eucalyptus.